Typically, biological materials refer to materials existing in or derived from living organisms. As the biological materials possess excellent biocompatibility, the biological materials are widely used in medical applications. To ensure safety of using the biological materials, the biological materials must be subjected to a strict sterilizing procedure in order to be suitable for use in living organisms.
Conventional methods for sterilizing the biological materials are as follows:
(1) Sterilization with 75% ethanol: immersing the biological materials in 75% ethanol. The disadvantage of this method is that the biological materials are easily denatured. Moreover, prior to use, the biological materials need to be rinsed. However, the rinsing may not completely remove the ethanol and ethanol residue may remain in the biological materials.
(2) Sterilization with radiation: irradiating the biological materials with rays or ultraviolet radiation to sterilize the biological materials. However, the energy of the rays is so high that some chemical structures of the biological materials are destroyed. Moreover, irradiating the biological materials with the rays has to be operated in a specific place with specific equipment. In addition, the ultraviolet radiation has a limited penetration distance, so is inefficient in sterilizing the biological materials that are mostly in three-dimensional shape.
(3) Sterilization with chemical bactericides: adding chemical bactericides into the biological materials to sterilize the biological materials. However, most of the chemical bactericides are toxic and are difficult to be removed. Therefore, sterilizing the biological materials with the chemical bactericides is only used in few fields and is impractical.
(4) Sterilization under high temperature and high pressure: this method results in denaturation of the biological material easily, even completely losing bioactivity of the biological material.
Each of the aforementioned sterilization methods has its drawbacks. People skilled in the art are anxious to design a sterilization apparatus that can be easily and widely used without causing damage to the biological materials.